Machines for carrying out principles of vertical tillage have grown in popularity in recent years. Such vertical tillage machines have typically employed gangs of generally flat coulters, as opposed to concavo-convex discs, that are disposed in straight-ahead, parallel alignment with the path of travel of the machine. The coulters may be provided with lateral projections such as waves or flutes to make them more aggressive as they cut through surface residue and engage, fracture and lift the soil. Generally speaking, it is not their objective to turn over and move significant amounts of soil to the side as they work, in contrast to disc machines wherein the discs are typically disposed at oblique angles to the machine's path of travel, but rather to create relatively narrow strips of tilled soil. Therefore, vertical tillage machines with rotating coulters are commonly used in the spring as pre-plant tools ahead of a planter for cutting plant residue left over from the previous fall harvest and for preparing an excellent seed bed. One such commercially successful vertical tillage machine has been available for several years from Great Plains Manufacturing, Inc., the assignee of the present invention, as the TURBO-TILL series of machines.
Because vertical tillage machines of this type employing rotatable coulters have only a limited ability to lift and move soil laterally to cover and incorporate residue, it has historically been necessary to use a separate more aggressive disc-type machine for fall tillage operations or other situations where significant soil displacement is desired. Yet, conventional disc-type machines are often not suitable for light spring operations, particularly ahead of no-till or minimum till planters. Thus, in the past, it has been necessary to have two separate machines to meet these two distinctly different needs, i.e., a vertical tillage machine for spring, seed bed preparation work and a disc tillage machine for fall, residue management work.
In one aspect, the present invention provides a highly versatile combination vertical tillage and residue management machine wherein the generally flat coulters may be angularly adjusted between a zero degree vertical tillage position in which the coulters are disposed straight ahead in parallel alignment with the path of travel of the machine and an oblique residue management position in which the coulters are disposed at up to a ten degree angle relative to the machine's path of travel. Preferably, when the gangs are in the residue management position, the coulters are disposed at no more than a six degree angle. Thus, the same vertical tillage machine can be used for either vertical tillage operations or more aggressive residue management operations.
Other aspects of the present invention are not necessarily limited to a combination vertical tillage and residue management machine. In this respect, the present invention provides for remote hydraulic adjustment of the gang angle from the seat of the towing vehicle, whether the tillage tools are rotatable coulters, discs, or other devices. The hydraulic actuators are directly coupled with front gangs, while mechanical linkage transmits the adjusting movement of the front gangs to a set of corresponding rear gangs to carry out simultaneous adjustment of both the front and rear gangs. The machine has left and right gangs on opposite sides of the fore-and-aft center line of the machine. The two left and right center gangs immediately adjacent opposite sides of the fore-and-aft axis each have their own hydraulic actuator but are mechanically interconnected at their proximal inboard ends by synchronizing apparatus that assures synchronized movement of the two separately powered gangs. If the machine is a multiple wing machine with a center frame section and a pair of left and right hinging frame sections on opposite sides of the center section, the hydraulic circuit for actuating the gangs may include a master-slave system for each left and right half of the machine. The master actuator on the center frame section controls successively reduced diameter slaves on the corresponding wing section.